Whereas flat smooth surfaces are generally relatively easy to clean by washing, regardless of orientation, uneven or otherwise irregular surfaces, especially if underfoot, are more difficult. Many displaced materials, plants, and even animals collect in the cracks, crevices, and interstices of roofs, grooved pavements, etc. Manual methods of washing or otherwise cleaning such surfaces are laborious, lengthy, and often not too satisfactory. Also footing is insecure on such surfaces, especially when appreciably inclined.
Machine-assisted methods of washing such surfaces are known, with rotary brushes, rim-fed as disclosed by Krause in U.S. Pat. No. 3,624,668 and alternatively center-fed as taught by Tissier in U.S. Pat. No. 4,000,538, or with jets and a vibrating tamper as disclosed by Conway in U.S. Pat. No. 3,711,891. However well such devices may work on carpets or flat surfaces, they leave much to be desired where unyielding irregularities collect dirt, grease, moss, seeds, etc., especially on sloping and/or terraced underlying surfaces, where my invention is particularly effective and meets a long-felt need.